In recent years, developments have been made for improving protection performance especially for the heads of occupants when the side of a vehicle is subjected to an impact force.
Japanese Patent No. 3510061, for example, proposes an occupant protection device configured to store a roof side airbag from a pillar along a roof side edge so that the roof side airbag is inflated in the form of a curtain along side window glasses when an impact force exceeding a certain level is applied.
The occupant protection device is configured such that the roof side airbag is stored in a pillar space and a roof space; an inflator is mounted to a roof side rail; the roof side airbag is mounted to the roof side rail by bolts at certain pitches; and the roof side airbag is connected to the inflator via a gas supply pipe. With this occupant protection device, when a sensor detects an impact force above a certain level applied laterally of the vehicle body, the inflator generates gas to inflate the roof side airbag along the side glasses toward the passenger compartment.
In this occupant protection device, however, when the roof side airbag, which is a one-piece bag across the entire longitudinal length of the vehicle, inflates, it deploys also to a seatbelt area, and can be hindered from deploying by a seatbelt. More specifically, there is a problem that when a three-point seatbelt device, which is fastened at a shoulder point, a waist point and an opposite waist point, is mounted to a pillar such as a center pillar, and a seatbelt is drawn out from a through ring disposed above the shoulder of an occupant to be worn by the occupant, for example, the roof side airbag located above the shoulder is in a position to interfere with the seatbelt when inflating and deploying, and the roof side airbag cannot deploy smoothly.
For proper inflation and deployment of the roof side airbag, straps are attached to front and rear end portions of the airbag. The straps are attached to brackets mounted to the vehicle body to maintain the tension of the airbag. In the related art, however, attachment of the straps to the brackets is done without regard to the movement of the roof side airbag during inflation and deployment. Specifically, a strap mounting hole formed in each bracket is a rectangular elongate hole, and has caused the problem of hindering the movement of the strap or causing the strap to be caught between the vehicle body and the bracket and preventing the strap from moving, leaving room for improvement.